Many different types of underground cable laying implements have been proposed for simultaneiously cutting a slit in the ground and laying a flexible cable therein and including vibratory means for the plow. While these prior art devices have proved to be successful, they have not always utilized the forces involved to an optimum due to the direction of the vibratory movement of the plow blade. Examples of devices of the prior art type are shown in the U.S. Pat. No. 3,575,006, issued Apr. 13, 1971; U.S. Pat. No. 3,590,588 issued July 6, 1971; or the U.S. Pat. No. 3,363,423 issued Jan. 16, 1968.